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(No Model.) 7 Sheets- Sheet 1.

C. BURGHER.

FIRE ALARM TELBGRAPH.

No. 871,878. Patented 001;. 18, 1887.

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FIRE ALARM TELEGRAPH.

170.371,87. Patented Oct. 18, 1887.

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(No Model.) 7 Sheets--Sheet 3.

' C. BURGHER. FIRE ALARM TELEGRAPH.

No. 371,876; Patented oct'. 18, 1887.

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C. BURGHER.

PIRE ALARM TBLBGRAPH.

'Patented Oct. 18, 1887..

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PIRE ALARM TBLEGRAPH.

170.871,87@ MPajelluf'ed Oct. 18, 1887.

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FIRE ALARM TBLEGRAPH. No. 371,876. Patented 18, 1887.

A CHARLES BURGHER, OF BOSTON, MASSACHUSETTS, ASSIGN OR TO THE AUTO- MATIC FIRE ALARM AND EXTINGUISHER COMPANY, (LTMITEDQ OF NEW` Youn, N. Y.

FlRE-ALARM TELEGRAPH.

SPECIFICATION forming part of Letters Patent No. 371,876l lated October 18, 1887.

Application filed June 12, 1886. Serial No. 204,919.

and exact description, reference being had to the accompanying drawings, forming part of this specification.

My invention relates to the class of electric signaling and iireialarm telegraph systems in which a central station is in constant'electrie communication with one or more local points for the purpose ot' receiving and recording signals or lire-alarms in a manner well known.

The principal object of my invention is to provide a more perfect system of iirealarm telegraph y, whereby the system at times auto-l matically adapts itself to the defective c onditions which arc continually occurring therein from accident or design, and whereby the system is always maintained in operative condition, anda signal or alarm circuit is constantly i established under the Various conditions hereinafter set forth.

To the above purposes my invention consistsinlhevariousnovclcombinationsand subcombinations of certain features, as hereinafter fully described and claimed.

In the accompanying drawings, Figure l represents a diagrammatic view of my invention, showing the arrangement-s, constructions, and disposition ofthe circuits and their contained apparatus, both at the central station and a local point. Fig. 2 represents a front sectional view taken on line 2 2, Fig. 3, of4 the wellknown i'orln of the fatkins signal-box'with the modifications and as used in my invention, as hereinafter set out. Fig. 3 represents a side sectional view of the signal-box, taken on line 3 3, Fig. 2. Fig. 4 represents an under side sectional view of the signal-box, taken on line 4 4, Fig. 2. Fig. 5 represents a perspective view of a portion of the signal-box as illustrated in Figs. 2, 3, and 4, showing the signal-transmitting wheels and their eo-operating contact-fingers and the switch springs lying beneath. Fig. represents a 'front sec tional view taken on line 6 6, Fig. 7, of my circuit-changing mechanism with the circuit- (No model.)

connections and as used in my system, as herev inafter set forth.

My circuit-changer is notherein claimed as of itself, for it forms the subject-matter of another application of mine for a patent, and is here merely claimed in connection with the signaling system hereinafter described.

Fig. 7 represents an under side sectional view of my circuit-changer, taken on line 7 7, Fig. 6. Fig. 8 representsa side sectional View 6o of my circuit-changer, taken on line 8 S, Fig.

6. Fig. 9 represents a perspective view of a portion of my circuit-changer asillustrated in Figs. l, 6, 7, and 8, showing my signal-trans mitting wheel and the circuit-changing wheels, with their cooperating contact-iingers and the eircuit-comiections, as hereinafter fully set out. Fig. l0 represents an underside View of a vibratory thermostat with a portion of the vibrating arm broken away. Fig. ll rep- 79 resents a sectional View of Fig. l0 on line l1 ll in said iigure. Fig. 12 represents a top plan view of an ordinary switchboard mech` anism as used in my system, showing the circuit-connections. Fig. 13 represents a side 75 elevation of Fig. 12. Fig. l/t is a diagrammatic view of the normallyvclosed metallic circuit, and Fig. l5 is a similar View of the. reestablished circuit after the thernilostat has switched the circuit and the circuitchanger 8o has shifted its parts.

In the said drawings like numbers and letters designate corresponding parts throughout.

Referring tothe drawings, in Figs. l, 2, 3, 4, and 5, M designates the signaling-box for transmitting electrically-predetermined number-signals, and is of the ordinary form Vof the NVatkins automatic lire-alarm signalbox, with the exception of my modifications 9o inarranging the circuits traversing the electro-magnet and slight changes in the circuitconnections, hereinafter alluded to. This signal-box consists of a baseboard upon which is mounted the signalstransmitting apparatus g 5 and the protective casing surrounding the same. This apparatus is operated by an ordinary spring-actuated clock-work, U, whose main arbor U has keyed thereon and revolv ing therewith the transmitting-Wheels V', V", Ioo

' cogs V on the other wheels.

V3, V, V, and T, and the check-disk W, which latter is provided with the peripheral notch W. The wheels V V2 V3 Vl Vf are uniform and have similarly disposed upon their peripheries the circuit closing and opening cogs V, respectively arranged side by side and in alignment; also, upon their peripheries are fixed the circuit closing and opening teeth X, which vary in number for each wheel. The wheel T is provided with cogs T, similar in number and arrangement to insulating material, is fastened upon the clockwork frame to one side of the transmittingwheels, and upon its under face are set hy means of screws o the contact-fingers c c2 v3 #125 and t t', which are iiat metallic strips arranged side byside, out of contact, and with their free ends disposed beneath the wheels and disk, mounted on the main arbor and within striking distance of the cogs and teeth thereon when the arbor is rotated.

Directly below block Q, and fast to the clockwork frame, is an insulating-block, It, upon the upper face of which is set the contact-strip r, with its free end lying beyond the block toward the transmitting-wheels, and upon the lower face of said block is afiixed the contactarm r', whose free end is in contact with the free end of strip r and extends therebeyond and carries the insulating-show12 upon its end.

This shoe r2 is adjusted to be tripped by cogs T on wheel T when revolved.

The operation of the clock-work Uis under control of the electro-magnets e and e2, each ofy fifty ohms resistance, and situated below the clock-work. The armature eis supported by lever Z, pivoted upon bar lc, and carries the hook h, which holds, releases, and catches ily 7L', according as the magnets e and e2 operate the armature e, thereby controlling the motion of the clock-work. The check-lever Z is also pivoted to bar k to the outside of the clockwork frame, and has its lower short arm secured to the back of armature e, and has its upper end arranged with a stud, Z2, which is kept in constant engagement with the periphery and notch W of the check-disk XV by means of the retracting-spring Z, attached hctwee'n the short arm of check-lever and the clock-work frame. The stud Z'l normally lies in notch WV', and the spring Z3 also servesto withhold the armature e from off the magnets. When the armature e is drawn down on the magnets, the stud Z2 is moved out of notch W, and hook h releases iiy h', and the clock-work is set in motion and continues to run until the notch W is again presented to stud Z2, which takes into it, while the short arm of check-lever Z raises the armature c from off the magnets, and hook h catches and holds the [ly h, thereby stopping the clock. A

The transmitting-wheels V, W, V3, V, V5, and T each have live of the circuit breaking and making cogs Vand T', respectively, which are similarly arranged on each wheel to transmitthe number-signal 131, while the teeth X The block Q, of

vary on each wheel and are designed to transmit the number of a certain iioor ofthe building in which the signal-box may be located. The transmitting-wheels are shown in normal positions with their respective contact-fingers in contact with the adjacent cogs V and T,

with the exception of finger t, which is nor--v and made and broken again as the wheels arev rotated, and the shoe r2 is tripped by each cog T sufliciently to cause its arm r to break and make Contact with the free end of strip i'. In the same manner will the teeth X on wheels V V2 V3 V* V5 each make and break contact with the respective ngers.

Upon the winding-arbor U of the clockwork is fixed theinsulating-eollar K, provided with a radial flange which at every complete revolution of said arbor presses and then rests against the tops of two of the three switchsprings O O O, placed uprightly upon the side of an insulating-block, K, set upon the clock-work frame. This collar is revolved in a direction opposite thc hands of a clock, and when it comes to rest against said switchsprings the limit ot' the motion of the clockwork U is reached, and the winding-arbor is turned backward to again wind up the clockwork. The inner spring, 0 2, is straight, and lies normally in contact with the pin Q3 on the clock-work frame, and thereby is kept in electric communication with said frame, which, through means ofthe main arbor U, is in communication with all the transmittingwheels mounted thereon. The middle spring, O, is similar to O2, and lies in contact with the connectingscrew K2, set in block K. The outer spring, O, is L-shapcd, with its short arm extending across the right-hand face, Fig. 2, of spring O and out of Contact therewith. When the iiange on collar K2 comes to rest against springs O' O2, the former spring breaks contact with screw K2 and makes with spring O, and the latter, O2, breaks with pin O3.

In the well-known form of the Watkins signal-box a horseshoe electro-magnet is employed, with a ground-wire traversing each arm thereof. I modify this feature of the signal-box by splitting the magnet and traversing magnet e with a line-wire and magnet e2 with a ground-wire. The switch J is used to ground box M through post 39, and thereby to transmit the number-signal 131, by means of wheel T and contact-linger t', in a manner hereinafter described.

The binding-posts 33 35 and 31 32 39 30 3l IOO IIS

are disposed at the upper and lower ends of 4improved signal system.

the base-board of the box, respectively, for joining up the circuits, as hereinafter explained.

In Figs. l, 6, 7, S, and 9 my circuit-changer N is illustrated as arranged and used with my The device in itself forms the sul'iject-matter of `another application of mine. This circuit-changerN consists ofthe base-board S, to which is fixed the ordinary clock-work, S, provided with a springmotor, operating the circuit-changing apparatus connected therewith. The binding-posts s' s2 s3 s s s S7 si* are arranged near one edge of the base-board, and S2 is a easing covering the apparatus.

Upon the main arbor s are the circuit-changing wheels C O2 C C, which turn therewith,

and are provided with the peripheral cogs d di d" d, respectively, which are situated side by side in a line. The trip-disk F is set fast upon arbor Lsgad j acent to the clock-work frame, and has upon its inner face two studs, F' F2. These wheels are insulated from their arbor and areA disconnected from each other. The transmitting-wheel P is keyed upon the end of arbor s, which gives an electric communication with frame Si, in turn connected by wire at the lower lefthand corner, Fig. 6, to the post s. The wheel P is provided with the circuit opening and closing peripheral notches P', and upon its outer face has a pin, P2, adjusted in alignment with lthe cogs d d di d, as shown.

The block Y, of insulating material, located upon the frame below and to one side ofarbor s, carries the fixed con tact-iin gers bb' b b'* b5 b" b? b8 b, the free ends of which lie beneath the transmitting-wheels and ont of contact therewith in the following` order: Finger b coacts with the pin P2; finger Z2 presses upon .the periphery of wheel I and breaks contact therewith through the notches P', lingers 7) b" and b5 b and bl bE and b" lie opposite the wheels C C2 C C, respectivel y, as enumerated, The normal relative positions of these wheels and their Iingers are shown in the drawings, and in this condition only one contact-finger, b2, is in Contact with its coacting wheel. The wheels are controlled, as hereinafter described, to rotate nearly fivesiXths of a revolution in the direction ofthe y arrow in Fig. 6, so that when the pin P2 and the several cogs d d2 d dL come around and press against their respective fingers the wheels will stop rotating, and then all the lingers will be and remain in contact with their coacting parts. During the fivc-sixths of a revolution the finger b2 will have passed over the two series of notches I u )on its wheel which are arranged to correspond to the break and make cogs on the transmitting-wheels of signal-box M. XV hen the wheels are started again, they will then turn through one-sixth of a revolution and come into their normal positions, as shown. This readj ustment is effected by hand. The connecting-screws 5 i 'il is 9 are set` down in the block Y so that their lower ends will come in contact with the lingers b5 b bT L8 b",

. respectively, when said fingers are normal and free from the cogs d d2 d dt, as shown, and be out of contact therewith when said fingers are raised by said cogs.

The electromagnets g g2, of s even and seventy ohms resistance, respectively, are mounted in the bracket g? and g5, and areeach traversed by the line-wire. The armature g, common to both magnets, is pivoted near its center by the screws g4 in the bracket g5. The retracting-springp has one end fixed tothe armature g near magnet g2 and the other end fixed to the tension-screw p', so that the armature is drawn away from magnet g2 and forced down on magnet g. The trip-lever f is pivoted upon the side of the clock-work frame by the bracket f, and at the lower end has the projection f2, bearing upon the end of armature g near magnetg, and isheld firmly thereon by means of the spring/3. The upper 'end of the trip-lever has a wedge shaped extension, f6, over the inclined face of which the studs F F2 are pushed by rotation of the disk F. By virtue of this construction when the magnet g2 draws down the adjacent end of the armature g the other end thereof slips from under the projection f2, which isjammed down between magnet g and armature g, and this movement causes the hook f", which is fixed upon the back of armature g, to release its confined ily f5, thereby starting the clock-work motion and moving the stud F off the extension ff. The motion continues until the stud F2 hits upon extension f, depresses that end of leverf, and raises the lower end of said lever, so that the projection is drawn out from the interposition between magnet g and armature g, whereby the armature g is closed on magnet g and the hook f* is adjusted to catch and hold tiyff and stop theclock-work.

In Figs. 1, l0, and 11, H designates a thermostat provided with a vibratory and weighted spring-arm. This, however, in itself is not ot' my invention, but forms the essence of an invention of one Joseph A. Miller. I have merely illustrated this thermostat as connected up in my improved system ofsignaling. This device consists of the securing-plate A, upon which is set the box A,'and both are made of suitable insulating material. The bindingposts ce, a', and a2 are disposed at opposite ends of the securingplate, respectively. The binding-screws c c'l are set in opposite sides of the box A in the same plane, but out of alignment, vand are adjustable lengthwise toward or away from each other, and form the electric back and front contacts, respectively, for the thermostat.

The contact-spring c is L-shaped and is set on the inside ot' the box A, and the free end lies a little below the front contact, c2. The metallic plate L is fastened over the open end of box A and projects to one side thereof in direction of front contact, c2. The vibratory curved arm L is provided with a weight, L, upon one end, and is passed into box A through the slot L2 in plate L, in which slot it is swiv` ICO IIC

ISO

eled on the screws L5 and vibrates thereon. l switch are on the normally-open ground-cir- In normal condition the weight L3 is held, as shown, by the clip L, which is made fast to the metallic plate L and the weight L3 by the easily-fused solder L", while the other end of arm L presses against back contact, c. When the heat fuses the solder and allows the weight to fall, the arm leaves back contact, c', and strikes upon contact-spring c, and then upon front contact, c2, and the vibrations ofthe said arm will make and break with contacts c2 c'a series of times, and tinally comes to rest against front contact, c2, and spring c. The vibratory arm L is in electrical communication with plate L, which is in turn connected to posta of wire 50. The contacts c and cl and post a are electrically connected by wires 51 and 52, and contact-spring c is connected by wire 53 with post a. In operative posit-ion the thermostat is secured by plate A in position of Fig. l1. j a

.ln Figs. 1, 12, and 13, Zdesignates an ordinary form of switch-board for electric circuits as used with my system. This board has disposed at one end four binding-posts, 60 62 and 61 63, in pairs, for the in and out going lines, respectively, of the system. i

The switch-arms 64, 65, and 70 swing on their pivoted ends and are adjustable upon the contact-buttons 66 67 68 and 69 71, respectively, which are electrically connected in an evident manner, as shown in the drawings.

` The holes 72, 73, and 76 are break-holes, which are tilled or bridged by the switch-plug 77, shown in its resting-hole, being transferred to the desired hole and there inserted. The bi nding-posts 74 and 75 are arranged at one end of the board Z and form the ground-connections for ground Z adjacent thereto. The switchboard Z is shown in normal condition, and obviously if the switch-plug be placed in hole 76 the ingoing and outgoing lines above alluded to will be short-circuited.

The thermostat l-I has its front and back contact-sin the same circuit, and also has a groundcontact, c. l therefore term the device a thermostatic switch,7 having three ways or contacts.

My fire-alarm system is operated on a complete metallic circuit normally closed and furnished with electric current from oftice battery 20, the poles of which are connected with switches 22 and 23, respectively, of switchboard 21, having adjacent ground 25, and from the poles over said switches run the negative and positive lines, respectively. rlhe relay-magnets 26 and 27 are situated in the metallic circuit, one near cach pole of battery 20, and normally have theirarmaturcs closed.

The tire-battery 50, also at the central station, has a ground, 55, a relay-magnet, 54, and a switch-board, 51, provided with contact 53 and switch-arm 52, whereby said battery may have its power put on either the positive or negative side of the metallic circuit and rcenforce battery 20, or battery 50 may be cut out. The tire-battery v50 and its relay and cuit hereinafter described. The batteries, their relays, switches, and grounds, just described, are all located at the central station. The mechanisms consisting 'of the switchboard Z, circuit-changer N, signal-box M, and thermostat H'are situated at a localpoint or building distant from the central.

The diagrammatic plan view of the system shown in Fig. 1 represents the system under normal condition. V

rlhe complete metallic circuit is normally closed, and leads by the positive pole from battery 20, through switch-arm 23, relay-magnet 26, over switch-board Z, to post s of circuit-changerN; thence it passes to connectingscrew t, to contact-finger b, post s, thence to split in wire at a point below signal-box M, Fig. 1, then back to circuit-changer and to post s, forming the first branch-point, from where it branches, and one branch leads as follows: From post si it passes over the retaining-magnet g', which has armature g held thereon by spring-pressure, as before described; thence it passes to connecting-screw t8, over contactlinger be, by wire to contact-linger b5, to connectingscrew post 8*,to post a in thermostat H, thence to contact c', arm L, plate L, to post a', and back to circuit-changer, to post s3, thence to contact-nger bl, connecting-screw il to post s', which forms the second .branchpoint of the branches, from where it goes by the negative line to switch-board Z, relay 27, switch 22, to battery 20. The other brauch leads from the first branch-point at post s2 of circuit-changer over the actuating-magnet g2, contact-ringer bt, over wheel l?, thence by arborover clock-work frameto thesecond branchlOO point post s', thence to line and to battery 20, as described. Considering this normallyclosed metallic circuit, when the t-hermostatio switch H is made to vibrate between the contacts c and the contacts c and c2 at the times when the arm L is out of contact with all of said contacts, the current will be orf of the retaining-magnet g and on the actuating-magnet g, so that a series of vibratory motions of the switch will serve to send,

a sufiicient number of impulses over actuating-magnet g'l to cause it to attract its armatureg and start the circuit-changer. When the vibration ofthe thermostats ceases,the normally-open metallic circuit will loe reestablished as follows: The cogs on the circuitchanging wheels and the pin P2 on the transmitting-wheel having come to rest against the several contact-lingers b b2 b3 I)4 b5 1)07 bg bq and .broken their connection with connectingfinger bl to post sa, to thermostat H,and therethrough in an obvious path to post s4 in eircuit-ehanger, contact-tinger b", cog el', to contact-iinger b, to post S7, thence to post 30 in signal-box M, over controllingmagnet e' to post 33, and over the positive line to battery 20. In this re established metallic circuit the contact-springs 1' and i", provided with the shoe r2, when tripped by cogs T' on wheel as before explained, will record their makes and breaks of their circuit on relays 26 and 27 when the circuit-changer has operated and the signal-box runs.

It will also be seen that in normal condition, if the metallic circuit be broken on the branch containing the retaining-magnet g', the circuit-changer will be started by the actuating-magnet gi receiving the full current from battery 20, and in operating the transmittingwheel P, with its coacting finger b2, will transmit the number 131 per notches P' twice, which will be recorded on relays 26 and 27.

The normally-open ground -cireuit leads from the ground-connection of the metallic closed circuit at central orifice over fire-battery 50, relay 54, by both the negative and positive lines of the normally-closed metallic circuit to arm L', and terminates at contact c2 in thermostat H. From the terminal c in thermostat it passes to post'35in-signa1-box M, over contact-nger c', wheel `V', arbor and clock-work frame to stud 0, spring-switch O2, thence to controlling-magnet c, to post 34, to switch-board Z, and to ground Z'. vVhen the ottico-'ground 55 finds ground Z by either the negative or positive line oi' the normallyclosed metallic circuit, this normally-open ground-circuit will be closed, and the controlling-magnet c2 being energized, the signal-box M will be started, and since said ground-circuit is preserved at one point over contactijnger c' and transmitting-wheel V', the circuit openings and closings thereby over either intact line of the metallic circuit will be recorded on the responsive relay -magnet 54. The wheel V' thus serves to record at the central station the number 131 per its cogs V for the building in which the apparatus is located and Sper its teeth X for the floor of the building on which the operating-thermostat is l0- cated. The openings and closings of the reestablished metallic circuit over the contactsprings r and r' merely record the confirmatory signal-number 131 on relays 26 and 27, according to the teeth T' on wheel T. Vhen the predetermined degree of temperature operates the thermostat H, as described,the continuity of the normally-closed metallic circuit is destroyed by the vibratory motion of the thermostat, which then serves to energize the actuating-magnet g2, located in the other branch from the thermostat,and thus start the circuit-changer. In the meantime, the contact c having been made a suiiicient number of times, the central ground, 55, inds local ground Z', and so energizes controlling-magnet e2 of the signal-box and starts the same,

which records its signal-number on relay 54, as before described. The intermittent current which is sent over magnet gl sufficiently to energize the same and start the circuitchanger is not sufficiently continuous to'alloW the transmitting-wheel P and contact-finger b2 to record the openings and closings per notches P. Vhen the circuit-changer comes to rest at ve-sixths of a revolutiomthe re established metallic circuit made through said circuitchanger will have its contact-springs 1' and r' record on relays 26 and 27 the signal-number 131, which thereby gives a signal confirmatory to the signal recorded in relay 54 by signalboX M.

The thermostatc switch H, I construct tok give between twenty and twenty-five vibrations, or any necessary number, which insures the passing of the intermittent current over actuatingmagnet g2 sufficiently to energize the same.

The signal-box M may be grounded by hand on the normally-open adjacent ground Z' by switching the arm J from left to right, Fig. l, thereby connecting arm Z'Z with arm J', which will give ground Z' to the central ground, 55, over both the positive and negative lines of the normally-closed and intact metallic circuit,to the split point 90 in said circuit, whence it passes to post 39, and over the connected arms Z2 and J', by wire to contact-finger t', over cogs T' on wheel T, thence over the clockframe to spring O2, traversing and energizing magnet c2, to post 34, thence to binding-posts 75 and 74, and to ground Z', thereby starting box M and recording the number-signal 131 on relay 54, according to the circuit openings and closings by nger t' and the cogs T', of uniform size. The normal condition of the Working circuit is not disturbed by this grounding by hand of box M to give a firealarm designating the building onl y.

The portion of the initial cog T' lying directly under contact-finger t is cut away so as to leave a very narrow piece to make and break with nger t. This is for the purpose ol' gaining a peculiar danger or trouble signal on relay 54 in case the box M is accidentally set ott-by being jarred, for instance. In this ease of accidental starting the signal 131 will be recorded on relay 54 by the central ground, 55, finding ground Z' over both the positive and negative lines of the normally-closed metallic circuit, to split post 90, thence to post 32, over spring O' to contact-linger t, cogs T' on wheel T, over frame ot' the clock-work and over spring 02, over magnet c2, which it energizes, thence by post 34 to ground Z' in board Z. The initial cog T', which the coacting contact-finger t makes and breaks with, is cut away, as described, and the first number recorded will be very brief and will thereby be recognized as an accidental alarm.

I have shown the use of a single thermostatic switch H in the system, which represents the eighth tloor of a building. Of course the number of switches H may be increased IOO IIO.

as desired. For instance, three more may be cut in on the branch with the one shown and connected up with signal-box M by posts 80, 8l, 82, and 83 in an obvious manner with contact-,fingers o2 c3 e", respectively.

The operations of my lire-alarm system will `non,T be considered with reference to defective conditions of grounds and breaks in the several parts thereof which are likely to occur.

In case of a break on the branch of the nor- Inally-closed metallic circuit containing the retaining magnet g', the occurrence of said break is made known at the central station by the current passing over the branch contain'- ing the actuating-magnet g2, thereby starting circuit-changer and recording over both positive and negative lines upon relays 26 and 27 the number-signals 131 131, as per notches in the transmitting-wheel I?, opening and closing said circuit by its coacting finger t?, as before described. Under this condition of the circuit-changer having .operated to re-establish the circuit a tire-alarm may be received on relay 54 by virtue of the normally-open groundcircuit being established over the intact line of the re-established metallic circuit, as before described for said open circuit. Considering that this break occurs in a building during the night when not accessible, the switchboard Z being located to the outside of said building, an operator goes to the building, according to the signal of defect having been announced by the circuit-changer, and manipulates the switch-board by removing switchplug 77 from its resting-hole and inserts it in break hole 76, thereby short circuiting the normally-closed metallic circuit from said local point and restoring to normal condition the' system for the other connected buildings in line therewith. It is obvious that this short-circuiting does not defeat the signal-box M from subsequently sending a rire alarm over the open ground circuit, as described, for the connections of the switch-board Z afford uninterrupted path therefor, as in the normal condition.

In the case of a break on the normally-closed metallic circuit outside of the branch just described, the same is denoted by the armatures of relays 26- and 27 falling away from their magnets and remaining so until the continu- 'ity of the circuit is restored by hand. Under this condition a Lire-alarm may be received on relay 54 from signal-box M over the intact line ofthe normally-closed metallic circuit, as described for the normally-open ground-circuit, since t-he circuit-changer and thermostatic Y switch remain unaffected.

, to destroy the effect of the defective ground on said normally-closed metallic circuit, and the system is then Worked on said latter circuit,

over which a tire-alarm may be recorded on.

relays 26 and 27 by the circuit openings and closings of the contact-springs r and r being tripped, as by the description hereinbefore given.

In the case of a short circuit on the normally-closed metallic 'circuit the thermostatic switch, circuit-changer, and signal-box act as described in case of no defect, and a fire-alarm may be recorded on relay 54 from signal-box M by the normally-open groundcircuit by three paths-viz., over each of the lines of the normally-closed metallic circuit and by the short circuit itself to the thermostatic switch.

In the case of the normally-closed metallic circuit having one line open and the other grounded, considering the condition of the positive line grounded and the negative open, switch-arm 22 of board- 2l.is moved ont-o ground' 25, thereby establishing the positive and negative lines as closed and open, respectively. Considering the condition reversedthat is, negative line grounded and the positive open-switch-arm 23 is grounded on ground 25 and switch-arm 52 is moved onto point 53, thereby making the negative and positive lines open and closed circuits, respectively.v Under these conditions the alarm may be received on the open circuits according to the cases described for the closed and open circuits, respectively. Under the conditions of a break on the.normallyclosed metallic circuit outside of a building and both ends grounded at said break, a nre-alarm may be received by opening switch-arm 52, so as to break ground 55, and working on the closed metallic circuit, as before described, and the re-established metallic circuit over springs r and r will record the fire-alarm.

Having thus described my invention,I claim as new and desireA to secure by Letters Patentl. In a fire-alarm system, in combination, a normallyclosed metallic circuit having branches therein and an included relay and a circuit-changer, substantially as described, having in one branch its retaining-magnet and in the other branch its actuating-magnet and transmitting device, whereby a signal may be recorded on said relay, substantially as described.

2. In a fire-alarm system, in combination, a normally-closed metallic circuit having branches therein and an included relay, an open metallic circuit and a signal-box included therein, and a circuitchanger, substantially' as described, situated in both of said circuits and having in one branch its retaining-magnet and in the other branch its transmitting-device and'actuating-magnet, whereby said circuit-changer may automatically record a signal upon said relay and close said open metallic circuit, substantially as described.

y 3. In a fire-alarm system, in combination, a normally-closed metallic circuit? having branches therein and an included relay, a normally-open metallic circuit and an includedsignal-box provided with a tripping device,and a circuit-changer, substantially as described, situated in both of said Acircuit-s and having in one branch its retaining-magnet and in the other branch its transmitting device and actuating-magnet, whereby said circuit-changer may automatically act in succession to record a signal and close the open metallic circuit and the tripping device may act to record a tire-alarm upon said relay, substantially as described.

et. In a tire-alarm system, in combination,

a normally-closed metallic circuit havingv ranches therein and provided with a normallyclosed ground-connection having a relay at the central station, a normally-open metallic circuit, a circuit-changer, substantially as described, situated in both of said metallic circuits and having its retainingand actuating magnets located respectively in said branches, and a signal-box included in said open metallic circuit, said boxhaving au open ground-connection and a controlling handswitch therefor, whereby said box may be grounded to record a fire-alarm upon said relay, substantially as described.

5. In a fire-alarm system, in combination, a normally-closed metallic circuit having branches therein and provided at the central station with a normally-closed ground-connection having a relay therein, a three-way thermostatic switch situated in one of said branches, a circuit-changer, substantially as described, having its retaining-magnet in the branch with the thermostatic switch and its actuating-magnet in the other branch, anda signal-box provided with an open ground-connection controlled by said switch, whereby said box may. record a tire-alarm upon said relay.

6. In a lire-alarm system, in combination, a normally-closed metallic circuit having branches therein and included relays and a normally-closed ground-connection also provided with a relay at the central station, a normally-.open metallic circuit, a three-way thermostatic switch adapted to make a series of contacts and located in one ofsaid branches, a circuit-changer, substantially as described, having its retaining-magnet in said branch with said switch and its actuating-magnet in the other said branch, and a signal-box located in said open metallic circuit and provided with a tripping device,and having an open groundconnection controlled by said switch, whereby said box may record a fire-alarm upon the relay in said closed gromid-connection, and the circuit-changer close the open metallic circuit, and the tripping device record an alarm upon the relays on said closed metallic circuit, substantially as described.

7. In a tire-alarm system, in combination, a normally-closed metallic circuithaving a relay and a grounding-switch in the positive and negative lines each and provided at the central station with a normally-closed groundconnection having a relay and a switch coutrolling both said positive and negative lines, a normally-open metallic circuit, a three-way thermostatic switch adapted to make a series of contacts and included in a branch of said closed metallic circuit, a circuit-changer, substantially as described, having its retainingmagnet in the branch with said tliermostatic switch and its actuating-magnet in a branch around said thermostatic switch, and a signalbox, substantiallyas described, locatedinsaid open metallic circuit and provided with an open ground-connection controlled by said thermostatic switch and by hand, substantially as described.

8. In a tire-alarm system, in combination, a normally-closed metallic circuit having at the central station a relay and grounding-switch in its positive and negative lines each and provided at the central station with a normally-closed ground-connection having arelay therein and a switch controlling both of said lines, and a local point in said closed metallic circuit containing the following elements, viz: an open metallic circuit, a three way thermostatic switch adapted to make a series of contacts and located iu a branch of closed metallic circuit, a circuit-changer included in said metallic circuits, substantially as described, a signal-box, constructed substantially as described, having an open ground-connection controlled by said thermostatic switch and by hand, and a short-circuiting device including both said positive and negative lines, whereby said circuit may be short-circuited from the local point, substantially as described.

9. A hre-alarm system consisting of a closed metallic circuit provided at the central station with relays and a closed ground-connection, also having a relay, and a series of local points located in said closed metallic circuit, each containing the following elements, viz: an open metallic circuit, a thermostatic switch adapted to make a series of circuit openings and closings and located in a branch of said closed metallic circuit, a circuit-changer included in said open and closed metallic circuits, substantially as described, and having its retaining-magnet in the branch with said thermostatic switch and its aetuating-magnetin a branch around said thermostatic switch, a signal-box provided with a tripping device and included in said open metallic circuit and having' an open ground-connection controlled by said therinostatic switch, and ashort-circuiting device inclndediu said closed metallic circuit, whereby said circuit may be short-eircuited, substantially as described.

l0. A fire-alarm system consisting of a closed metallic circuit having at the central station a relay and a grounding-switch in the positive and negative lines each, and also having at the central station a nornially-closed ground-connection provided with a relay and a switch controlling saidA lines, and a series ot' local points located in said closed metallic circuit, containing the following elements,v1z: an open metallic circuit, a tlireeway thermostatic switch adapted to make a series of contacts and included in a branch of said closed metallic circuit, a circuit-.changer included in said open and closed metallic circuits, substantially as' described, a signal-box provided with a tripping device and having an open groundconnection controlled by said thermostatic switch and by hand, and a short-clrcuiting device included in said closed metallic circuit, whereby said circuit may be short-circuited from a l( c il point, substantially as described 1l. 4In a lire-alarm system, a normally-closed metallic circuit normally grounded at the central station, a three-way tlierlnostatic switch at a point in said circuit, and a ground adjacent thereto, said switch adapted to make a series of short contacts, thereby opening and [5 closing said closed metallic circuit and closing and opening said adjacent ground, or operating reversely.

In witness whereof I have hereunto set 'my hand.

, CHARLES BURGHER.

Witnesses: v

M. F. BLIGH,'

JOSEPH A. MILLER, Jr. 

